The water developers of Los Angeles and their lawyers knew from the first paragraph that they were in trouble. Court opinions about Western water invariably carried a pragmatic, detached, utilitarian tone. This case was supposed to be about the needs of a thriving but thirsty metropolis - about civilization itself - not about some remote lake.

Yet the ominous words of the California Supreme Court rose up from the page, hinting that this lake was a worthy place, perhaps a place to be respected and protected, perhaps even a place whose intrinsic values might rise above the long-exalted right to divert water:

"Mono Lake, the second largest lake in California, sits at the base of the Sierra Nevada escarpment near the eastern entrance to Yosemite National Park. The lake is saline; it contains no fish but supports a large population of brine shrimp which feed vast numbers of nesting and migrating birds. Islands in the lake protect a large breeding colony of California gulls, and the lake itself serves as a haven on the migration route for thousands of northern phalarope, Wilson's phalarope and eared grebe. Towers and spires of tufa on the north and south shores are matters of geological interest and a tourist attraction."

It had not always been that way. Mark Twain came through during the gold rush days. "Mono Lake," he wrote in Roughing It, "lies in a lifeless, hideous desert ... This solemn, silent, sailless sea - this lonely tenant of the loneliest spot on earth - is little graced with the picturesque." With his youthful abandon, Twain expressed pronounced reservations about the desirability of bathing in alkaline, sulfurous, salty Mono:

"This water is not good for bruised places and abrasions of the skin. We had a valuable dog. He had raw places on him. He had more raw places on him than sound ones. He was the rawest dog I almost ever saw. He jumped overboard one day to get away from the flies. But it was bad judgment. In his condition, it would have been as comfortable to jump into the fire. The alkali water nipped him in all the raw places simultaneously, and he struck out for the shore with considerable interest. He yelped and barked and howled as he went - and by the time he got to the shore there was no bark to him - for he had barked the bark all out of his inside, and the alkali water had cleaned all the bark off his outside, and he probably wished he had never embarked in any such enterprise."

Even John Muir - who lovingly sent out so many superlatives about California's wild country - found little good to say about Mono Lake. Mono Pass was a "glorious gateway" to the Mono Lake region. A tributary to the lake (probably Rush Creek) was a "happy stream," "one of the finest ... I ever saw." The lake itself, however, was only a "bare lake 14 miles long." As late as 1972 another California original, Clint Eastwood, remembered Mono Lake for its "eeriness' and, upon revisiting it, immediately said, "Yeah, this is the spot." Thus did Mono - as a metaphor for Hell - become the setting for High Plains Drifter.

The Los Angeles Department of Water and Power, therefore, had little concern about public sentiment in the 1930s when it applied for water permits to divert the flows of four of the five streams feeding into Mono Lake. Nor did the law seem to present any barriers. Water was there for the taking, first come, first served.

Los Angeles had already dried up Owens Lake to the south. The other large depressions that received water from streams draining the east side of the Sierra Nevada - Pyramid Lake, Walker Lake and Carson Sink - had all been fundamentally reworked in the name of greening the desert. Los Angeles had bought up the private land around Mono Lake and the local band of Paiutes - residents at Mono for 8,000 years - had been pushed out. Why would anyone object to drawing down Mono Lake?

Many of the locals did protest at hearings for the permits. There is scant evidence of any larger public concern. One person who did raise his voice was 18-year-old Martin Litton, later colleague to David Brower and, with his classic wooden dories, Grand Old Man of the Colorado River. In 1935, Litton saw what LADWP was up to and wrote the Los Angeles Times: "When our City of Angels will wantonly dry up beautiful, mysterious Mono Lake to selfishly add a few unnecessary gallons to an already adequate supply, things are going a little too far ... Mono Lake is a gem - among California's greatest scenic attractions - a beautiful and historic landmark which must not be destroyed."

But the times were wrong for protecting a place like Mono. The public was quiescent about the natural world. The law gave LADWP a straight shot at the water rights and in 1940 it got the permits. And once you had a water right, you had it forever - free and clear.

Los Angeles plunged ahead, constructing diversion works on the streams feeding Mono and building a canal down to its Owens Valley facilities for transport to Los Angeles, some 300 miles from Mono Lake.

The lake, deprived of its sustenance, began to drop and became saltier and more alkaline. Thirty years later, LADWP winched the pressure up and accelerated the lake's decline: the original diversions had taken half of the stream flows but in 1971, the city (using the 1940 permits) doubled its take. Four streams ran essentially dry, leaving only water from Mill Creek.

Eventually the lake dropped 45 feet. This created alkali flats which, combined with high winds common to the area, resulted in toxic dust storms that violated the Clean Air Act.

But the most heartfelt public response involved the birds. Although too salty and alkaline for most life, including fish, the Mono Lake ecosystem is nonetheless very productive. The food chain begins with green algae, a microscopic, one-celled plant that converts solar energy. Brine flies (Twain complained about them - -a belt of flies 100 miles long') and brine shrimp (Twain called them "a white feathery sort of worm, one-half an inch long') feed on the algae. The brine shrimp, numbering an estimated 4 trillion, swarm in the lake during the summer, with the next generation wintering over as eggs. The brine flies number in the millions and have a total weight of 2,000 tons.

The brine shrimp and flies, which live off the algae, are in turn feasted upon by some 80 species of migrating birds that visit the lake during the spring and summer. Over 1 million birds have been counted at Mono in a single day. By the mid-1970s, it had become clear that the diversions were going to kill off the ecosystem that made this profusion of avian wildlife possible. The algae would not survive increased salinity. The flies and shrimp could not survive without the algae. The birds would survive as species, but in reduced numbers - and not at Mono.

It takes many heroes and a long story to protect a large natural area in this complex age. Certainly that is true with Mono Lake, which has become the site of one of the most inspiring success stories in the modern American West.

On one level, a person can see the results in court decisions, administrative orders and settlement agreements. The definitive ruling on the critical issue of lake level is a 1994 decision by the California State Water Resources Control Board setting the level at 6,392 feet. In turn, that order ultimately traced to the 1983 California Supreme Court decision, quoted earlier, in National Audubon Society vs. Superior Court of Alpine County. The National Audubon opinion is one of the most luminous judicial decisions ever handed down in any field of law. It certainly must be ranked as one of the five or 10 leading environmental decisions by American courts.

National Audubon broke new ground by applying the public trust doctrine to water diversions. Previously, individual developers held an absolute right to divert water; no consideration was given to the larger public interest.

The National Audubon court, however, found that navigable watercourses (basically, large rivers and lakes that had historically been used for some commercial purpose) were held in trust for all the public. LADWP's 1940 water rights, therefore, had to be balanced against the public trust. As the court said, even though such factors had never traditionally been taken into account in granting Western water rights, "Mono Lake has long been treasured as a unique scenic, recreational and scientific resource, but continued diversions threaten to turn it into a desert wasteland." Los Angeles' right to divert, in other words, had to take into account the biological, scenic and recreational values of Mono Lake.

Ultimately Mono Lake has become one of the main lenses through which Americans, and especially Westerners, have learned to look at the natural world. Like the sere tundra of Alaska's North Slope and the rocky canyons of southern Utah, not long ago Mono Lake was a place ignored or scorned by our society. We are blessed in that respect by the light-hearted humor of Mark Twain, for he gives us a milepost to remind us how far we have come.

One of the essential qualities of Mono Lake, though not officially declared so by Congress, is that it is wild. And, finally, we have come to revere wilderness. We understand that it is messy - inefficient, disorganized, inconvenient. Mono can be mucky, smelly and hard on the skin, a place where you can get stuck, sunburned, frozen and swarmed by flies. It is also a place where you can find a dazzling array of birds, long vistas, startlingly new and craggy shapes, and the lazy pace of solitude.

Charles Wilkinson is Moses Lasky professor of law at the University of Colorado School of Law. This essay was adapted from his introduction to Jim Stimson's forthcoming book of photographs, Mono Lake: Explorations and Reflections, published by Orion Publications Inc., HC79, Box 69, Crowley Lake, CA 93546. Hardcover: $55, 115 pages.